RISS 검색 - 국내학술지논문 상세보기

다국어 초록 (Multilingual Abstract)

Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for sensing and damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory/field tests and possess significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and SHM applications. These films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. This study started with spin coating dispersed ZnO- and PVDF-TrFE-based solutions to fabricate the piezoelectric nanocomposites. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5 % increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled (at 50 MV-m-1) to permanently align their electrical domains and to enhance their bulk film piezoelectricity. Then, a series of hammer impact tests were conducted, and the voltage generated by poled ZnO-based thin films was compared to commercially poled PVDF copolymer thin films. The hammer impact tests showed comparable results between the prototype and commercial samples, and increasing ZnO content provided enhanced piezoelectric performance. Lastly, the films were further validated for sensing using different energy levels of hammer impact, different distances between the impact locations and the film electrodes, and cantilever free vibration testing for dynamic strain sensing.

참고문헌 (Reference)

1 Wang, Z. L., "Zinc oxide nanostructures: growth, properties and applications" 16 (16): R829-R858, 2004

2 Loh, K., "Zinc oxide nanoparticle-polymeric thin films for dynamic strain sensing" 46 (46): 228-237, 2010

3 Gao, H., "Ultrasonic guided wave annular array transducers for structural health monitoring" 2006

4 Gaur, M. S., "Thermally stimulated dielectric properties of polyvinylidenefluoride-zinc oxide nanocomposites" 103 (103): 977-985, 2011

5 Ahlborn, T. M., "The state-of-the-practice of modern structural health monitoring for bridges: a comprehensive review" Transportation Research Board 2010

6 Kawai, H., "The piezoelectrcity of poly(vinylidene fluoride)" 8 : 975-976, 1969

7 Hilczer, B., "The method of matching resonance frequencies in coupled transmitter PVDF/TRFE diaphragms" 7 (7): 498-502, 2000

8 Greeshma, T., "The influence of individual phases on piezoelectric coefficient of PZT-PVdF composites" 393 (393): 88-93, 2009

9 Ulusoy, H. S., "System identification of a building from multiple seismic records" 40 (40): 661-674, 2011

10 Gu, Y., "Surface strain distribution method for delamination detection using piezoelectric actuators and sensors" 2011